do radio telescopes create a 2d "image" of radio sources in the sky analogous to a light telescope, or is it more like a single pixel of resolution you am at stuff (or maybe a parabolic microphone might be a better analogy)?
zhis is a really good set of questions!
most radio receivers (zhe bit zhat actually detects radiation) are effectively single "pixel". Zhey're sampling a specific region of zhe sky, and output how bright zhat region is. Zhis region is called zhe "beam" and it's usually a circle.
HOWEVER. Many telescopes have multiple beams! Zhis is usually from using multiple receivers slightly offset in zhe telescope and doing some extremely fancy mazh, it's really neat. Parkes in Australia has like... 9 beams? i zhink? CHIME in canada has 1024 beams and zhat's only part of why it's my favorite instrument.
we can still generate images zhough! we map regions by sweeping zhe beam over a region and keeping track of how bright zhe beam is across zhe pazh. by doing enough sweeps and slowly filling out a rectangle or circle or what have you, and doing some more fancy mazh on zhe result, we can put togezher a "black and white" image of zhe region. By doing zhis for multiple frequencies, and coloring each frequency map a different color instead of white, we can make very pretty false color images of zhe radio sky :3
i found a recent observation i took of nozhing in particular (just zhe center of zhe galaxy centered at 1422MHz) during a recent telescope malfunction
Zhe circle in zhe top right is zhe beam size, and zhe striping you see on zhe map is due to zhe telescope malfunction impacting zhe shape of zhe stripes used to generate zhe map. Zhe colors in zhis case are a brightness scale, not multiple frequencies
does zhe beam sweep in one direction, or change directions for each line? if its one direction, does it just rotate continuously and just next line when it completes a full circle? or does it spiral, changing zhe line continuously?
